Flotation machine for the treatment of ores and the like



R. FORTUNE Oct. 21, 1941.

FLOTATION MACHINE FOR THE TREATMENT OF ORES AND THE LIKE File?! Aug. 17, 1939 4 Sheets-Sheet l INVENI'OB RONALD FORTUNE;

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Oct. 21, 1941. R. FORTUNE FLOTATION MACHINE FOR THE TREATMENT OF ORES AND THE LIKE 4 Sheets-Sheet 2 Filed Aug. 17, 1939 INVENTOR I RONA).. FORTUNE A Oct; 21, 1941. R. FORTUNE 2,259,744

FLOTATION MACHINE FOR THE TREATMENT OF ORES AND THE LIKE Filed Aug. 17, 1959 4 Sheets-Sheet 4 1N VEN TO B RONALD-PO RTUNE ATTORN S Patented Oct. 21, 1941 FLOTATION MACHINE FOR. THE TREAT- MENT F ORES AND THE LIKE Ronald Fortune, Toronto, Ontario, Canada Application August 17, 1939, Serial No. 290,557

Claims.

This invention relates to new and useful improvements in an apparatus and process used in the art of flotation and concentration of ore pulp in mining and like industries.

The object of my invention is to provide a machine of the flotation type which will rapidly separate the precious metals from the mineral gangue and in which means are provided to trap and classify certain elements of the ore being treated.

Another object is to provide a flotation machine in which agitation of the pulp is eifected within one zone in each cell which is isolated from the concentrate-discharge of the machine so that said agitation will not disturb the flow of the concentrates from the machine but will assist in discharging said concentrates in an evenly controlled, continuous sheet of flow.

Another object is to provide a flotation machine in which the settled portion of non-floating particles of ores will be positively trapped within the machine, and in such a manner that the said settled portion, once trapped, will be prevented from further mixing with the remaining elements of the ore under treatment.

A further object is to provide means to convey the trapped products through a plurality of cells, and to classify them in transit, and to extract the settled portion from the machine, for further treatment.

A still further object is to provide a flotation machine with means to afford a plurality of fixed and also a plurality of controllable discharge levels within the machine and from the machine.

According to my invention, I provide a flotation machine having one or more individual cells. Means are provided within the machine for the continuous circulation of ore pulp in each individual cell and in sucha manner as to positively eliminate short-circuiting of treatment through one or more cells and to effect continuous selective separation of concentrates, middlings and gangue.

Means are also provided to-thoroughly agitate the ore pulp, mechanically and pneumatically and in such a manner, that the elements of the ore being concentrated, will be carried on the surface of th fluid within the machine, on a froth film, and discharged therefrom in a direction transversely to the flow of pulp through the machine.

I also provide in the machine, means for the selective separation of the elements of the material under treatment and controllable and fixed of different specific gravities, at diflerent levels, from and through the cells comprising the machine.

In the accompanying drawings which illustrate forms of my invention:

Figure l is a front elevation of a four cell machine: two of said cells having diiierent sections removed to clarify the construction and only two cells showing the outside construction.

Figure 2 is a plan view of the machine shown in Figure 1, taken on the line 22 of Figure 1.

Figure 3 is a cross-sectional elevation of one of th classifying cells taken on the line 3-3 of Figure 1.

Figure 4 is a cross-sectional elevation of one of the straight flotation cells taken on the line 44 of Figure 1.

Figure 5 is a partial sectional elevation of the machine taken on the line 5-5, Figure 2, with the extractor or classifier screw removed from cell number l5.

Figure 6 is a partial sectional elevation taken on the line 6-6, Figure 1.

Figure 7 is an end elevation taken on the line 1-1, Figure 2.

Figure 8 is an end elevation taken on the line 8-8, Figure 2.

Figure 9 is a front view of one of the cells, showing one modification of the inlet feed to the rotating agitator.

Figure 10 is a partial sectional elevation similar to that shown in Figure 9, but with the agitating screw shown in position.

Referring more particularly to the drawings and to simplify the reading thereof, the machine shown in Figure 1 has four cells marked ll, l3, l5 and I6. These cells are in numerical order, starting from right to left, as that is the direction of flow of material through the machine. Each cell is of substantially the same construction except that cells II and I3 have the settling chamber casting 33 shaped to form a plain settling and circulating chamber whereas in cells l5 and IS the settling chamber casting is formed to accommodate the classifying extractor screw it at the bottom of the settling chamber l! as shown in Figure 3. Cell H is shown as an outside view, and consists of a front plate I 9, rear plate 20, flow plate 2|, and froth guide 22. These plates I9, 20, 2| and 22 are the outside plates and form the main body of th machine in conjunction with the end plates 23 and 24. The corner 25 between thei'eed plate 26 and the base plate 2| is well rounded to form a feed director and housing means for regulating the discharge of elements for the agitator 2l. hereinafter described. The

Junction between the plates 2|! and 22 is well Jnunded off to form a flow director. -Spaced from the front plate I! and extending downwardly to the curved junction between the .base and front plate is the feed plate or partition 23- which has two ports 23 formed therein in proximity to the agitator 21, said ports being located at opposite comers of the agitating cham. her as shown in Figs. 1 and 5. The space between the plates It and 20 forms a feed chamber 29. .Extending across each cell and resting on the tops of plate I! and overhanging plates 23 and 43 is the concentrate discharge chute 34, which guides the concentrates into the launder 3| shown by dotted lines in Figure '7. This chute slopes downwardly towards the frontof the machine to accelerate the discharge of concentrates from the machine. Extending upwardly and rearwardly is the underface 32 of the settling chamber casting 33, which forms the base of the settling chamber II. This settling chamber casting extends from end plate to end plate of each cell. The plates 32 and 2| converge towards the rear of the machine, forming between them an agitating chamber 34. The upper curved portion 33 of the settling chamber casting conforms partially to the curve made by the plates 20 and 22 thus forming between them a flow chamber and orifice.

The curve 35 extends between the end plates 23 and 24 of each cell and continues in a tangentially horizontal position to direct the flow from the agitating chamber towards the discharge chute 30, but is positioned preferably below the lip 33 formed between the plate 31 and the chute 30. The space encircled by the curved flow guide 35 forms in operation a quiescent section around the communication port 33 formed in the end plate 24 through which the tailings discharge is controlled from cell to cell by way of pipe elbows The deflector guide 22 extends across the full width of the cell andis directed upwardly and forwardly towards the front of the an entire bank of cells comprising a whole machine, that is, the flow from cell i! to cell l3 and out through the discharge opening 44, which may consist of a flanged part 44a of the discharge end housing. This helical extractor is horizontally disposed and is such that the settled portion of the non-floatable material is carried at a controlled level from end to end of .a plurality of cells machine to form a froth director, to guide the froth in an even flow towards the lip 36.

Positioned between plates 23 and 22 and settling chamber wall 32 are guide vanes 39 to diffuse the turbulence created in the agitating chamber 34 into a smooth flow through the orifice between 22 and 35. Adjustable gate valves 43 (Fig. 1) are provided to control the degree of opening of the ports 4| and to control the degree of. opening of the ports 42 as shown in cells II and I3. Rotatably mounted in suitable bearings 43 and at the lowest point in the settling chamber i1, said lowest point being formed between the junction of plate 23 and casting 33, is the gangue classifying helical screw extractor II. This helical screw moves at a comparatively slow speed so that it will disturb the settled gangue sufficiently to allow the lighter particles of the settled material to free themselves and flow through the ports 42 formed in the plate 26 and in a position above the central axis of the helical extractor. The action of this extractor is to classifythe material which has settled according to its speciflc gravity. These ports 42 are preferably long narrow slots which or from feed end to discharge end of an entire bank of cells comprising a whole machine.

There is no lifting of the settled heavy particles thus preventing same from re-circulating with the pulp under treatment in the cell.

Adjustable headgates 45 (Figs. 1, 3 and 4) are provided to control the level of the fluid circulating from the settling chamber into the feed chamber. Attached to the headgate 44 is the screw stem 46 which is operated by the handwheel 41.

The ports 28 from the feed chamber 23 into the agitating chamber 34 are positioned preferably below the central axis of the agitator screw so that the pulp enters the said agitating chain--- ber at the point where the vanes of the helical agitator are at their point of maximum propulsion. These agitating screws 21 are preferably of the double lead helical type and in each cham-- her the said helicals extend from the sides toward the centre of the cells. The reason for this construction' is that it creates two equally opposed axial flows converging at the centre of the cell to obtain maximum emulsiflcation and to lift the material, and to propel same in an upwardly and rearwardly direction as shown by the arrows 43.

The double axial current provided by the opposing screw action is such that it is balanced and results in complete emulsiflcation of fluid in the agitating chamber. It also results in directing the flow of emulsified or conditioned pulp to-.

wards the flow guides 35 and 22.

The'helical agitating screws are rotatably supportedin bearings 48 (Fig. 5) mounted in and sealed between the flanges ll. At the centre of each cell and mounted between the right and 'left hand agitators is the diffuser II which consists of a wheel having vanes 52, which on rotation lift the heavy material at the cell centre and force same into the flow of pulp.

Atmospheric air is drawn through the vertical pipes 53 into the horizontally disposed pumping cylinders 54 (Fig. 5) which enc'ase part of the helical screw agitators 2I'which form a positive pumping zone at the opposite ends of the cell :0

as to induce two equal and opposite atmospheric air streams into the fluid upon rotation of the agitators. Part of the cylinder '4 draws air through the ports 55 while the other part encloses the feed ports 28 to eflect two equally and oppositely balanced streams of emulsified fluid, converging at the centre of the cell as indicated by the arrows 53.

Air, or any other fluid, aisointroduced into the agitating chamber through the perforated cores 51, which are connected to an air supply pipe 12 (compare Figs. 3,4 and 6).

The helical agitator shaft end 21a and classifying extractor shaft end its (Fig. 1) may be driven at a relative speed through any suitable form of chain or gear reduction.

The end plate 24 at the discharge end of each cell carries a chamber 63, the bottom of which is feed end of the machine toward the discharge positioned below the tailings discharge opening valve 40.

38 which communicates concentrically about its horizontal axis with the bottom of the pipe elbow 6|. The elbow 6| in the chamber 60 at the left hand end of Figs. 1 and 7 is shown provided with an adjustable tubular weir 62 which is attached to the screw stem 63 and is vertically controlled by the handwheel 64. Tailings discharged through the drainage outlet 65 in the bottom of each chamber 60 gravitates through pipe 66 into the feed chamber 29 of the cell adjacent in sequence of treatment.

In operation pulp enters cell It through the pipe 61 into the feed chamber 29. The material gravitates toward the openings 28 and is directed thereto through the medium of the bevelled deflector 68, which divides said material in directly opposite flows towards the sides of the feed chamber. The material then enters the agitating chamber at the point of maximum propulsion of the agitating screw 21 at each end of the cell at which point the agitating screws are surrounded by the cylinders 54 to provide a positive pumping action for the fluid as it gravitates through the ports 28 and into the path of the rotating agitators. Air is drawn into the extreme ends of the cell through the vertical twin pipes 53 entering the cylinders through the ports 55 in two equal and opposite streams to be thoroughly emulsified into the cycling pulp streams at 28.

The rotation of the double helical agitators propels the double axial flow of material towards the centre of the cell converging same in an evenly balanced manner, thus creating intense emulsification without beating the pulp against the sides of the cells, to produce a very finely emulsified pulp and an evenly controlled depth of clean concentrate. Air is also introduced into the pulp through the perforated core 51 which has a part 51a situated above and parallel to that portion of the agitator 21 which is exposed between the cylinders 54. At the centre of the cell and rotating with the agitating helicals is the diffuser having vanes 52 which serve to pick up heavy particles and'lift same into circulation in the agitating chamber. The helical agitators are preferably of the double lead equally opposed type and are adapted through their construction to converge the material toward the centre of the cell.

The agitated or conditioned pulp is directed upwardly and rearwardly as indicated by the arrows 48, which show the direction of flow. The material passes between the flow guides 35 and 22, which form between them an orifice to direct the flow of pulp in a direction indicated by the arrows 68a. The concentrate, in froth form, is directed toward the discharge '30 and the middling toward the controlled head valve opening 69 for re-circulation. Sedimentation takes places between the aforementioned orifice and the bafile plate 31 and head valve 45. The material in the settling chamber i1 is in a substantially quiescent state around the port 38 which conveys the tailings through the pipe elbow GI and into the overflow chamber 60.

In the straight flotation type cells H and I3 the middlings continually overflow the head valve 45 for re-circulation and the non-floating material is bled through ports 4|, the degree of opening of said ports being controlled by the In the classifying type cells l5 and It the middlings overflow the head valve 45 for re-circulation. 'The heavier material subsides to the bottom of the chamber l1 and is conveyed therefrom by the movement of the helical classifying extractor l8. The rotation of this extractor is comparatively slow and is such that the non-floating particles are trapped and classifled in transit through the cells. The lighter or refloatable particles are releasedthrough the ports 42 for re-circulation'in the cell circuit. The non-floating particles trapped in the bottom of the settling chamber l1 are conveyed by'the classifying-extractor-screw through the cylinder 1| and into settling chamber of the next cell. This process of classifying the material in the settling chamber and extracting an underflow of oversize or non-floating material is adaptable to any number of cells comprising the machine.

It should be noted in the foregoing description that cells II and I3 are straight continuous cycle flotation cells whereas cells I5 and I6 are similar in all respects except that the continuous classifying extractor I8 and cylinder 1! are added to effect a continuous classification of the settled material in the chamber l1 through the medium of said helical extractor and is continuous throughout a plurality of cells, and at no point does the trapped non-floating material enter into re-circulation; in other words, the settled portion of the non-floating material or gangue is conveyed from cell to cell and expelled from the machine at a level 44, and is independent from the feed opening 61 or the tailings discharge pipe 66.

For the flotation of ores which can be readily conditioned by chemical reagents and therefore do not require prolonged agitation, also where the pulp is conditioned ahead of flotation, the agitating screws 21, agitating shaft 21a. as well as the supporting bearings 49 are eliminated. In this manner the cells may be operated by air-lift displacement. Air, under pressure, is admitted and atomized through the perforations 51 (Fig. 6) causing the pulp to continuously circulate around the settling chamber in the direction of the arrows 48 and 68a and into the feed chamber 69 (Fig. 4) thus effecting and completing the same flow cycle as already described but without the aid of the rotating agitators.

Having thus described my invention, what I claim is:

1. In a flotation machine, a cell having a substantially V-shaped bottom, a substantially yertically disposed feed chamber at the front of the machine, said chamber having an outlet at the bottom thereof adapted to communicate with the remote corners of the bottom of the cell, horizontally opposed, spiral agitators arranged to receive the material from the feed chamber and to project it upwardly through the flow chamber of the cell and baflle means within the cell adapted to form a guide for the agitated material on its lower side and a flotation-separation-settling chamber, hereinafter called the settling chamber, on its upper side and means ber and discharging said concentrate from the cell.

4. In a flotation machine, a cell having formed therein. a feed chamber, an agitating chamber and a settling chamber, said feed chamber being at the front or the cell, and the bottom of the agitating chamber sloping up-,

wardly and rearwardly and substantially parallel to but spaced from the bottom of the settling chamber, means formed in the feed chamber to allow communication between the feed chamber and the agitating chamber near the bottom corners thereof, means within the teed chamber iordeflecting the pulp towards the communicating means, horizontally opposed, spiral agitators within the agitating chamber to circulate the material therein towards the settling chamber, means for guiding and discharging the froth from the settling chamber, means for returning the overflow from the settling chamber into the feed chamber and means for continuously classifying the gangue in the settling chamber. a

5. A device according to claim 4 in which the gangue classifying means comprises a submerged spiral conveyor adapted to force the heavier particles towards the outlet at one corner of the settling chamber, and means to allow the lighter particles -to -overflow into the feed chambers, and means to convey said heavier particles throughout a plurality of settling chambers in the cells comprising the machine.

RONALD FORTUNE. 

